Near-field imaging of plasmonic nanopatch antennas with integrated semiconductor quantum dots

Abstract

Plasmonic nanopatch antennas that incorporate dielectric gaps hundreds of picometers to several nanometers thick have drawn increasing attention over the past decade because they confine electromagnetic fields to grossly sub-diffraction-limited volumes. Substantial control over the optical properties of excitons and color centers confined within these plasmonic cavities has already been demonstrated with far-field optical spectroscopies, but near-field optical spectroscopies are essential for an improved understanding of the plasmon–emitter interaction at the nanoscale. Here, we characterize the intensity and phase-resolved plasmonic response of isolated nanopatch antennas by cathodoluminescence microscopy. Furthermore, we explore the distinction between optical and electron beam spectroscopies of coupled plasmon–exciton heterostructures to identify constraints and opportunities for future nanoscale characterization and control of hybrid nanophotonic structures. While we observe substantial Purcell enhancement in time-resolved photoluminescence spectroscopies, negligible Purcell enhancement is observed in cathodoluminescence spectroscopies of hybrid nanophotonic structures. The substantial differences in measured Purcell enhancement for electron beam and laser excitation can be understood as a result of the different selection rules for these complementary experiments. These results provide a fundamentally new understanding of near-field plasmon–exciton interactions in nanopatch antennas, which is essential for myriad emerging quantum photonic devices.

Correlative Nanoscale Imaging of Strained hBN Spin Defects

“…The heterogeneity of the V B – PL is illustrated in Figure , which shows the NMF decomposition of a PL spectrum image of the same flake acquired with a 2.2 mW laser excitation. NMF is a popular, computationally inexpensive tool for extracting sparse, physically relevant data from hyperspectral data sets that assume that a spectrum image results from the linear combination of non-negative constituent spectra. , The PL component 1 in Figure a,b has a peak at 600 nm that is consistent with the un-irradiated background hBN PL spectrum in Figure b, and it exhibits a strong spatial correlation with the un-irradiated hBN. Likewise, PL component 3 in Figure a,d is consistent with the measured substrate luminescence.…”

Angle-resolved polarimetry of hybrid perovskite emission for photonic technologies

“…Additionally, in the field of nanophotonics, CL microscopy has been used to map nanoscale electromagnetic modes in plasmonic and all-dielectric metamaterial systems. 41,[50][51][52] In other remarkable measurements, CL microscopy was used to probe other physical processes such as Purcell enhancement using plasmonics, [53][54][55][56][57] dispersion of quasiparticles such as surface plasmon polaritons 58,59 and collective Bloch modes in photonic crystals. [60][61][62][63] In this work, we adapt a recently developed technique in cathodoluminescence spectroscopy to access the full polarization state of emission from a large-grain hybrid perovskite thin film and highlight the effect that a single boundary has on the polarization and angular profile of the emitted photons.…”

“…Additionally, in the field of nanophotonics, CL microscopy has been used to map nanoscale electromagnetic modes in plasmonic and all-dielectric metamaterial systems. 41,50–52 In other remarkable measurements, CL microscopy was used to probe other physical processes such as Purcell enhancement using plasmonics, 53–57 dispersion of quasiparticles such as surface plasmon polaritons 58,59 and collective Bloch modes in photonic crystals. 60–63…”

Correlative nanoscale imaging of strained hBN spin defects

“…NMF is a popular, computationally inexpensive tool for extracting sparse, physically relevant data from hyperspectral datasets that assumes that a spectrum image results from the linear combination of non-negative constituent spectra. 36,37 PL component 1 in Figs. 2(a) and 2(b) has a peak at 600 nm that is consistent with the un-irradiated background hBN PL spectrum in Fig.…”